Heretofore, various types of signal devices or apparatus have been utilized to detect an undesirable predetermined high or predetermined low fluid pressure in fluid lines or fluid apparatus for pressure vessels. Such signal devices have included, for example, visually observable signals, as well as audible signals, or electronically transmitted signals to a remote location. Corrective action may follow the indication or detection of an undesirable fluid pressure.
Visual indicators heretofore have, for example, utilized extendible rods with brightly colored outer ends, such as red, which are extended for observation into a visible area when a predetermined high fluid pressure is reached in an associated flow line or pressure vessel. However, fluid communication through the indicator with the chamber containing the leaking fluid by another device, such as a sealant injector, has not been accomplished heretofore. Normally, other separate devices not associated with the fluid indicator or detector have been provided in order to take corrective action for the leaking fluid.